Sealing apparatus and manufacturing process of soft article having sealed portion

ABSTRACT

Disclosed is a sealing apparatus wherein, as a drum ( 5 ) and a rotary base ( 6 ) are rotated together, a follower ( 10   a ) of a rocking support member ( 9 ) rockably provided on the outer periphery of the rotary base ( 6 ) is guided along a cam groove ( 15   c ) of a cam member ( 15 ) to drive the rocking support member ( 9 ) to rock. When the rotary drum ( 5 ) reaches a predetermined rotational position, an anvil ( 14 ) supported by the rocking support member ( 9 ) is urged onto a horn ( 8 ), and then, when it reaches another rotational position, the anvil ( 14 ) is moved away from the horn ( 8 ). Since the anvil ( 14 ) is driven by the rocking motion of the rocking support member ( 9 ), entire operation becomes quite simple, and a continuous soft work can be certainly clamped between the horn ( 8 ) and the anvil ( 14 ).

TECHNICAL FIELD

[0001] The present invention relates generally to a sealing apparatusfor forming sealed portion in a continuous soft work for forming softarticle, such as disposable diaper, sanitary napkin and so forth, and amanufacturing process of such soft article having sealed portion. Moreparticularly, the invention relates to a sealing apparatus and amanufacturing process, which can certainly perform sealing operationwith simple operation.

PRIOR ART

[0002] For example, Japanese Patent Application Laid-Open No. 10-513128(PCT/US96/00618) discloses an apparatus for manufacturing soft articlesuch as diaper, as non-individual body, by providing ultrasonic seal toa continuous web at regular intervals.

[0003] In the above-identified publication, an ultrasonic sealingmechanism constituted of a plurality of ultrasonic horns and anvils isprovided in a rotary working drum for rotation together with the rotaryworking drum. The web is wrapped around the outer peripheral face of therotary working drum to be fed from upstream side and downstream side byrotation of the rotary working drum. The ultrasonic horn is driven by acam for reciprocation in width direction on the outer peripheral face ofthe rotary working drum. Within the rotary working drum, the anvils areprovided in opposition to the ultrasonic horns. Then, while thecontinuous web is fed by rotation of the rotary working drum, theultrasonic horn is moved transversely in the width direction on the webfor a given distance for forming line form ultrasonic sealed portions inthe web.

[0004] However, in the sealing apparatus disclosed in Japanese PatentApplication Laid-Open No. 10-513128, the operation of reciprocal motionof the ultrasonic horn in the width direction on the outer peripheralface of the rotary working drum, is performed by cam action. Therefore,reciprocating speed of the ultrasonic horn is required to be variedaccording to variation of rotation speed of the drum. Accordingly,moving speed of the ultrasonic horn is varied depending upon productionspeed to vary a time among a pressure and the time as sealing conditionsto make it difficult to achieve good seal. Namely, in the sealingapparatus disclosed in the above-identified publication, since cam shapeand drum diameter are limited, only production speed correspondingthereto can be achieved. Accordingly, when the production speed is to bevaried after production of the sealing apparatus, an allowable range forvarying the production speed is structurally quite limited.

[0005] On the other hand, upon continuously sealing absorbent article,such as diaper, it is typical that rubber or gather provided in the webis to be subject to the ultrasonic seal together with the web. In caseof the product having the rubber or gather, undulation is formed in theweb. When sealing operation for such web is performed by means of thesealing apparatus disclosed in Japanese Patent Application Laid-Open No.10-513128, the reciprocating ultrasonic horn is moved up and downdepending upon the undulation to possibly cause variation of pressure tobe applied to the web. Therefore, difficulty is encountered in achievinguniform ultrasonic seal in the web. This can result in fluctuation offinishing and/or strength of the sealed portion.

[0006] Furthermore, it requires complicate control of an air cylinder soas to control the air cylinder to apply a pressurizing force to theultrasonic horn when the ultrasonic horn comes into contact with theweb, and to control the air cylinder to release the pressurizing forceon the ultrasonic horn when the ultrasonic horn is moved away from theweb.

[0007] Also, upon sealing the web for producing the absorbent article,the thickness of the web tends to be different in the portions to besealed. In this case, when the ultrasonic horn and the anvil arepressurized by a single pressurizing means, the portion of the webhaving larger thickness is given greater pressurizing force than thatgiven to the portion of the web having smaller thickness so that weldingis dominantly progressed in the larger thickness portion in comparisonwith the smaller thickness portion. Therefore, the web in the largerthickness portion becomes stiff to differentiate sealing strength andtaste of finishing in the sealed portion.

DISCLOSURE OF THE INVENTION

[0008] The present invention has been worked out in view of theforegoing shortcomings in the prior art. It is therefore an object ofthe present invention to provide a sealing apparatus and a manufacturingprocess of soft article having sealed portion superior in manufacturingability in simple construction and achieving uniform seal.

[0009] Another object of the present invention is to provide a sealingapparatus and a manufacturing process of soft article having sealedportion, which can uniformly weld a portion to be sealed in a soft workhaving locally different thicknesses and prevent occurrence of portionshaving difference in the sealing strength and taste of finishing.

[0010] According to a first aspect of the present invention, there isprovided a sealing apparatus for forming sealed portions in a soft workcontinuously fed thereto, the sealing apparatus comprising: a rotatingportion; rotating driving means for driving the rotating portion torotate; and a plurality of sealing mechanisms arranged along a rotatingdirection of the rotating portion to move along with the rotatingportion, each sealing mechanism including a first clamping member and asecond clamping member for clamping the soft work therebetween within apredetermined angular range with respect to a rotation center of therotating portion for forming the sealed portions in the soft work,

[0011] wherein in each sealing mechanism, the first clamping member islocated on the side of the rotation center of the rotating portion toorient a seal opposing surface thereof outwardly in a normal directionextending from the rotation center, the second clamping membercorresponding to the first clamping member is located outside of thefirst clamping member in the normal direction, and the second clampingmember is pivotably supported on the rotating portion for pivotingbetween a claming position, in which a seal opposing surface thereof isurged toward the seal opposing surface of the first clamping member, anda retracted position located away from the first clamping member, and

[0012] wherein rocking driving means is provided for driving the secondclamping member to pivot as the rotating portion rotates so that thesecond clamping member is located in the clamping position within thepredetermined angular range and located in the retracted position withinanother angular range so as not to interfere with feeding of the softwork into the sealing mechanisms and ejecting of the soft work from thesealing mechanisms.

[0013] With the construction of the first aspect of the invention as setforth above, the second clamping member forming the sealing mechanismcan be radially pivoted away from the radially arranged first clampingmember to be placed in the retracted position. Therefore, the secondclamping member can be moved between the clamping position forperforming sealing operation and the retracted position not interferingwith transportation of the continuous soft work only by simple rockingor pivoting motion. Also, since sealing operation is performed bycontacting and releasing the first clamping member and the secondclamping member, sealing operation can be performed at high speed.

[0014] For example, the continuous soft work includes at least a sheetwhich can be fusion-bonded. The continuous soft work may further includeliquid absorptive bodies spaced apart from each other in a feedingdirection thereof and supported by the sheet, and sealing may beeffected in a condition where each liquid absorptive body is locatedbetween adjacent sealing mechanisms and the sheet is folded back.

[0015] By positioning the liquid absorptive body between adjacentsealing mechanisms, the sheet can be certainly sealed at the portionwhere the liquid absorptive body is not present.

[0016] Preferably, the rotating portion includes a rotary drum, and thefirst clamping member is arranged inside of the rotary drum so that theseal opposing surface of the first clamping member is located at aposition projecting from an outer peripheral face of the rotary drum.

[0017] With this construction, the folded sheet can be certainly sealedin the condition where the liquid absorptive body is located betweenadjacent sealing mechanisms and on the outer peripheral face of therotary drum.

[0018] Preferably, the seal opposing surface of the second clampingmember as pivoted to the retracted position is pivoted over about 90°with respect to a rotation center axis of the rotating portion.

[0019] By pivoting the second clamping member over the foregoing angleto the retracted position, the second clamping member can be certainlyretracted to the position not interfering with transportation (feedingand ejecting) of the continuous soft work.

[0020] For example, the rocking driving means is formed from a camprofile fixed at a position opposing to the rotating portion and afollower to move along the cam profile as the rotating portion rotatesfor pivoting the second clamping member between the clamping positionand the retracted position.

[0021] In this case, the cam profile may be defined by a continuous camgroove extending to surround the rotation center of the rotating portionbut spaced away from the rotation center.

[0022] For example, the follower is mounted on a rocking support membersupporting the second clamping member so that the rocking support memberis pivoted between the clamping position and the retracted position bymovement of the follower along the cam profile. In an alternative, theremay be provided a rocking support member supporting the second clampingmember and a link mechanism provided between the rocking support memberand the follower so that the rocking support member is pivoted betweenthe clamping position and the retracted position via the link mechanismby movement of the follower along the cam profile.

[0023] As set forth above, by providing fixed cam profile and pivotallydriving the second clamping member with taking rotating motion of therotating portion as driving power source, it becomes unnecessary toprovide another driving power source, such as cylinder mechanism or thelike, for pivoting the second clamping member per the sealing mechanism.

[0024] In the first aspect of the invention, it is also preferred thatthe rotating portion includes a rocking support member pivotablysupported by a rocking shaft, and the second clamping member issupported on the rocking support member via an elastic member so thatwhen the second clamping member is pivoted to the clamping position, thesecond clamping member is biased toward the first clamping member by anelastic force developed by the elastic member.

[0025] By biasing the second clamping member toward the first clampingmember via the elastic member, uniform pressure can be easily applied torespective portions of the soft work with the seal opposing surface ofthe second clamping member and the seal opposing surface of the firstclamping member even when the soft work has a structure havingunevenness.

[0026] According to a second aspect of the present invention, there isprovided a sealing apparatus comprising: a sealing mechanism having afirst clamping member and a second clamping member for clamping afusion-bondable soft work therebetween for forming sealed portions inthe soft work; and driving means for driving the second clamping memberto clamp the soft work between the first clamping member and the secondclaming member and to move away from the first clamping member,

[0027] wherein the second clamping member is supported on a supportingmember via an elastic member and the supporting member is driven by thedriving means so that the second member is biased toward the firstclamping member by an elastic force developed by the elastic member, andthe elastic member has a deformable casing into which fluid isintroduced.

[0028] In the foregoing second aspect of the invention, since theelastic member having the casing (e.g., bag shaped casing) into whichfluid is introduced, is employed, the second clamping member can bebiased to follow unevenness of the soft work or difference of thicknessof the soft work, so that such soft work can be clamped between thefirst clamping member and the second clamping member as uniformly aspossible. As a result, quality of sealed portion can be improved.

[0029] For example, the soft work is continuously fed to the sealingapparatus and a plurality of sealing mechanisms are arranged atintervals along a feeding direction of the continuous soft work so thatthe sealed portions are formed in the continuous soft work at intervalsalong the feeding direction by means of the sealing mechanisms.

[0030] Preferably, the sealing apparatus further comprises a rotatingportion, and a plurality of sealing mechanisms are arranged at intervalsalong a rotating direction of the rotating portion and the soft work iscontinuously fed to the rotating portion so that, as the rotatingportion rotates, the sealed portions are formed in sequential order bymeans of the sealing mechanisms.

[0031] For example, the continuous soft work includes a sheet which canbe fusion-bonded and liquid absorptive bodies spaced apart from eachother in a feeding direction thereof and supported by the sheet, andsealing is effected in a condition where each liquid absorptive body islocated between adjacent sealing mechanisms and the sheet is foldedback.

[0032] Here, it is preferred that the sealing apparatus furthercomprises pressure setting means for varying pressure of fluid withinthe casing.

[0033] By providing the pressure setting means, the pressure in thecasing can be set at an optimal value depending upon kind of the softwork. Therefore, the soft work can be clamped between the secondclamping member and the first clamping member under an optimal pressure.

[0034] Preferably, a plurality of elastic members for supporting thesecond clamping member are provided in the supporting member. In thiscase, more preferably, the sealing apparatus further comprises pressuresetting means for individually setting pressure of fluid withinrespective casing of the plurality of elastic members.

[0035] By biasing the second clamping member with the plurality ofelastic members, the soft work having uneven profile or having portionsof different thicknesses can be clamped with a uniform clamping forcebetween the second clamping member and the first clamping member.

[0036] For example, the sealing mechanism is an ultrasonic sealingdevice, and one of the first clamping member and the second clampingmember is a horn and the other is an anvil.

[0037] However, it is, of course, possible to perform heat sealing withthe first clamping member and the second clamping member of the sealingmechanism.

[0038] According to a third aspect of the present invention, there isprovided a method for manufacturing soft articles respectively havingsealed portions, comprising:

[0039] forming sealed portions in a continuous soft work by clamping thesoft work between a first clamping member and a second clamping member,the first clamping member and the second clamping member forming asealing mechanism; and

[0040] cutting the soft work before, simultaneously with or after theforming step,

[0041] wherein the second clamping member is biased toward the firstclaming member via an elastic member and the elastic member has adeformable casing into which fluid is introduced.

[0042] In the soft articles, such as disposable diaper, sanitary napkinand so forth produced by the foregoing manufacturing method, material ofthe soft work, such as sheet and so forth, can be uniformlyfusion-bonded in the portion to be sealed, to thereby improve quality ofthe sealed portion.

[0043] In the third aspect of the invention, for example, a plurality ofsealing mechanisms are arranged at intervals along a feeding directionof the continuous soft work so that the sealed portions are formed inthe continuous soft work at intervals along the feeding direction bymeans of the sealing mechanisms. Preferably, a plurality of sealingmechanisms are arranged at intervals along a rotating direction of arotating portion and the continuous soft work is fed to the rotatingportion so that, as the rotating portion rotates, the sealed portionsare formed in sequential order by means of the sealing mechanisms.

[0044] For example, with fluid pressure in the casing being set at apredetermined value, optimal sealing condition can be set depending uponstructure and/or thickness of the soft work.

[0045] More preferably, a plurality of elastic members are provided andrespective elastic members bias the second clamping member. In thiscase, it is preferred that internal pressures of the plurality ofelastic members are set independently.

[0046] By independently setting the internal pressures as set forthabove, uniform fusion-bonding quality can be obtained even when thecontinuous soft work has portions having different thicknesses in aregion where the sealed portions are to be formed.

[0047] For example, in case where the continuous soft work has portionshaving different thickness in a region where the sealed portions are tobe formed, it is preferred that internal fluid pressure of the elasticmember biasing the second clamping member toward a portion having largerthickness in the soft work and internal fluid pressure of the elasticmember biasing the second clamping member toward a portion havingsmaller thickness in the soft work are set independent of each other.

[0048] Here, the continuous soft work may include a sheet which can befusion-bonded and liquid absorptive bodies spaced apart from each otherin a feeding direction thereof and supported by the sheet, and sealingmay be effected at positions between adjacent liquid absorptive bodiesin a condition where the sheet is folded back.

[0049] For example, in order to make the quality of the sealed portionuniform, it is preferred that the set pressure of the fluid in theelastic member for applying the biasing force to the portion havingsmaller thickness is set higher than the set pressure of the fluid inthe elastic member for applying the biasing force to the portion havinglarger thickness.

[0050] In the third aspect of the invention, too, the sealing mechanismmay be an ultrasonic sealing device, and one of the first clampingmember and the second clamping member may be a horn and the other may bean anvil.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be understood more fully from thedetailed description given hereinafter and from the accompanyingdrawings of the preferred embodiment of the present invention, which,however, should not be taken to be limitative to the invention, but arefor explanation and understanding only.

[0052] In the drawings:

[0053]FIG. 1 is a section of a sealing apparatus according to a firstembodiment of the present invention as taken along line I-I of FIG. 3;

[0054]FIG. 2 is a perspective view for explaining a rotating portion ofthe sealing apparatus;

[0055]FIG. 3 is an explanatory illustration showing operating conditionof the sealing apparatus;

[0056]FIG. 4 is an exploded perspective view showing a structure of arocking support member;

[0057]FIG. 5 is a front elevation showing a shape of a cam member on theside of a stationary portion;

[0058]FIG. 6 is a side elevation showing a condition where an anvil ismoved at a retracted position away from a horn;

[0059]FIG. 7A is a side elevation showing a condition where the rockingsupport member is pivoted to contact the anvil to the horn;

[0060]FIG. 7B is a side elevation showing a condition where the anvil isurged to the horn under pressure with compressing an elastic member;

[0061]FIG. 8A is a perspective view showing a developed condition of acontinuous soft work;

[0062]FIG. 8B is a perspective view of the continuous soft work in thecondition supplied to the sealing apparatus;

[0063]FIG. 9 is a section showing a condition where the continuous softwork is clamped between the horn and the anvil, where the section of thesoft work is taken along line IX-IX of FIG. 8B;

[0064]FIG. 10 is a section showing a condition where the continuous softwork is clamped between the horn and the anvil, where the section of thesoft work is taken along line X-X of FIG. 8B;

[0065]FIG. 11 is a vertical section of a sealing apparatus according toa second embodiment of the present invention;

[0066]FIG. 12 is a front elevation showing a structure of a cam member;

[0067]FIG. 13 is a side elevation of a rocking support portion; and

[0068]FIG. 14 is an explanatory illustration of a piping for supplyingair to an elastic member.

BEST MODE FOR IMPLEMENTING THE INVENTION

[0069] The present invention will be discussed hereinafter in detail interms of the preferred embodiment of the present invention withreference to the accompanying drawings. In the following description,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be obvious, however, tothose skilled in the art that the present invention may be practicedwithout these specific details. In other instance, well-known structuresare not shown in detail in order to avoid unnecessary obscurity of thepresent invention.

[0070]FIG. 1 is a vertical section of a sealing apparatus according to afirst embodiment of the present invention as taken along line I-I ofFIG. 3, FIG. 2 is a perspective view for explaining a rotating portionof the sealing apparatus, FIG. 3 is an explanatory illustration showingoperating condition of the sealing apparatus, FIG. 4 is an explodedperspective view showing a structure of a rocking support member, FIG. 5is a front elevation showing a shape of a cam member on the side of astationary portion, FIG. 6 is a side elevation showing a condition wherean anvil (second clamping member) is moved at a retracted position awayfrom a horn (first clamping member), FIG. 7A is a side elevation showinga condition where the rocking support member is pivoted to contact theanvil to the horn, and FIG. 7B is a side elevation showing a conditionwhere the anvil is urged onto the horn under pressure with compressingan elastic member.

[0071] In a sealing apparatus 1 shown in FIG. 1, a bearing portion 3 isprovided on a stationary table 4 as stationary portion. A rotary shaft 3a is rotatably supported by ball bearings 3 b held in the bearingportion 3. In FIG. 1, a rotation center axis of the rotary shaft 3 a isshown by O-O. On a base end portion of the rotary shaft 3 a on rightside in the drawing, a timing wheel 2 having teeth on the circumferenceis fixed. On the timing wheel 2, a cogged belt is wrapped around. Thecogged belt is driven by a driving force from a driving source having anot shown motor for applying the driving force to the timing wheel 2.Then, the rotary shaft 3 a is continuously driven to rotate at aconstant angular velocity in counterclockwise direction in the conditionas viewed from left side of FIG. 1. In the shown embodiment, rotatingdriving means is formed from the driving source, the cogged belt and thetiming wheel 2.

[0072] On the rotary shaft 3 a, a rotary base 6 to be a rotating portionis rigidly secured. On the rotary base 6, a rotary drum is secured. Therotary base 6 is placed in opposition with the stationary table 4 inparallel relationship.

[0073] As shown in FIGS. 1 and 2, on the outer peripheral face 5A of therotary drum 5, a plurality of rectangular windows 5 a elongated in thedirection parallel to the rotation center axis O-O are formed. Therectangular windows 5 a are arranged at an equal pitch incircumferential direction. In the shown embodiment, the windows 5 a arearranged in six angular positions 60° apart from each other with respectto the rotation center axis O-O.

[0074] The rotating portion is provided with a sealing mechanism. Thissealing mechanism has first and second clamping members for clamping andsealing a continuous soft work therebetween. In the shown embodiment,the sealing mechanism is an ultrasonic sealing mechanism, of which thefirst clamping member is a horn 8 and the second clamping member is ananvil 14.

[0075] The horns 8 and the anvils 14 are both provided on the rotatingportion for rotation together with the rotary base 6 and the rotary drum5. The horns 8 are secured on the rotary base 6 within the rotary drum5. The horns 8 and ultrasonic generating means 7 connected to the hornsare arranged radially about the rotation center axis O-O. Here, theangular positions of the horns 8 and the ultrasonic generating means 7match the angular positions of the windows 5 a. Respective horns 8 areexternally projected through the windows 5 a of the rotary drum 5 tohave seal opposing surfaces 8 a at the leading ends thereof. The sealopposing surfaces 8 a of the horns 8 are oriented outwardly in normaldirection (radial direction) about the rotation center axis O-O andlocated parallel to the rotation center axis O-O. Projecting height ofeach of the seal opposing surfaces 8 a from the outer peripheral face ofthe rotary drum 5 is h.

[0076] The rotary base 6 is of hexagonal shape. Rocking support members9 are provided on the outer periphery portion of the rotary base 6. Eachrocking support member 9 is constructed to include a rocking portion 10and a holding portion 11. The rocking portion 10 and the holding portion11 are fixed with each other. The rocking portion 10 is formed intosubstantially fan shaped configuration. By a rocking shaft 10A providedat the center of curvature of the fan shape, the rocking portion 10 ispivotably supported with respect to the outer periphery portion of therotary base 6. The rocking shaft 10A is oriented perpendicular to therotation center axis O-O. Thus, the rocking support member 9 ispivotable about the rocking shaft 10A between clamping position andretracted position.

[0077] A cam member 15 is rigidly secured on the surface of thestationary table 4 in opposition to the rotary base 6. As shown in FIG.5, when viewed from the front side, the cam member 15 is of partlycut-out disc shape. The cut-out portion is indicated at 15 a.

[0078] The center of the cam member 15 matches with the rotation centeraxis O-O of the rotating portion. On the surface of the cam member 15, agroove portion 15 b is formed between an inner radius R1 and an outerradius R2 about the rotation center axis O-O. As shown in FIG. 1, across-sectional shape of the groove portion 15 b is arc-shape of radiusr1 about a pivoting center of the rocking portion 10 (center of therocking shaft 10A). As shown in FIG. 5, a concave surface of the grooveportion 15 b is of doughnut shape extending entire circumference aboutthe rotation center axis O-O. As shown in lower part of FIG. 1, in thecut-out portion 15 a of the cam member 15, the outer periphery side ofthe groove portion 15 b is cut out.

[0079] On the concave surface of the groove portion 15 b, a cam groove15 c to be a cam profile is formed. As shown in FIG. 1, the cam groove15 c is recessed in a direction perpendicular to a tangential line L-Lof the curve of the concave surface of the groove portion 15 b (orientedin radial direction with respect to the axial center of the rockingshaft 10A). On the circumferential edge of the rocking portion 10, afollower 10 a is provided. The follower 10 a is a rotatable roller. Inthe alternative, the follower 10 a may be a non-rotatable projection.When the rotary base 6 is driven to rotate, the follower 10 a is movedalong the cam groove 15 c. In the shown embodiment, the cam member 15and the follower 10 a form rocking driving means for rocking the rockingsupport member 9.

[0080] As shown in FIG. 5, the cam groove 15 c extends along an arc ofconstant radius about the rotation center axis O-O at a position themost distant from the rotation center axis O-O within an angular rangebetween angular positions A2 and A3, and also extends along an arc ofconstant radius about the rotation center axis O-O at a position theclosest to the rotation center axis O-O within an angular range betweenangular positions A0 to A1.

[0081] Accordingly, while the follower 10 a moves from the angularposition A1 to the angular position A2, the rocking support member 9 ispivoted toward the outer peripheral face 5A of the rotary drum 5 toreach the clamping position, and while the follower 10 a moves from theangular position A2 to the angular position A3, the rocking supportmember 9 is maintained in the clamping position, as shown in upperportion of FIG. 1. On the other hand, while the follower 10 a moves fromthe angular position A3 to the angular position A0, the rocking supportmember 9 is pivoted toward the stationary table 4 about 90° to reach theretracted position, and while the follower 10 a moves from the angularposition A0 to the angular position A1, the rocking support member 9 ismaintained in the retracted position, as shown in lower portion of FIG.1.

[0082]FIG. 4 shows the holding portion 11 as viewed from the sideopposed to the rotary drum 5. Within the holding portion 11, an elasticmember 13 is mounted. On the elastic member 13, the anvil 14 as thesecond clamping member of the sealing mechanism is supported.

[0083] As shown in FIG. 4, the holding portion 11 comprises: a rear sideportion having a fixing surface 11A, on which the rocking portion 10 issecured; a bottom side portion having a mounting surface 11B, on whichthe elastic member 13 is secured; and two frame portions 11 a and 11 aon 1 ft and right sides thereof. In the holding portion 11, therefore,openings 11C and 11C are formed on the left and right sides, and anopening 11D is formed between the two frame portions 11 a and 11 a to beopposed to the rotary drum 5. As shown in FIG. 4, the rocking portion 10has a supporting hole 10A1 to receive the rocking shaft 10A forpivotably supporting the rocking portion 10.

[0084] The elastic member 13 has: a flexibly and elastically deformablebag shaped body (casing); a disc-shaped supporting plate 13A mounted onthe top of the bag shaped body; and a disc-shaped fixing plate 13Bmounted on the bottom of the bag shaped body. The bag body of theelastic member 13 is made of an elastically deformable material, such asrubber, or a composite material, such as rubber combined withreinforcing member. By supplying an air as working fluid into a hollowportion of the bag body, the bag body functions as air damper or airspring. Here, the internal pressure of the bag body is set at apredetermined value by the supplied air pressure.

[0085] Both the supporting plate 13A and the fixing plate 13B areprovided with vertically extending tap holes 13 a. The fixing plate 13Bis further provided with a nozzle 13 b, to which an air pipe isconnected. The internal pressure of the elastic member 13 can be set byair pressure introduced through the air pipe and the nozzle 13 b. Meansfor setting internal pressure of the elastic member 13 has aconstruction comparable with that discussed later with respect toanother embodiment with reference to FIG. 14. Specifically, the airpressure to be supplied to each of the elastic members 13 provided in aplurality of sealing mechanisms can be set independently of the other.

[0086] The elastic member 13 is installed in the holding portion 11 insuch a state that its radially expanded portions protrude outwardlythrough the openings 11C and 11C. The tap holes 13 a and 13 a formed inthe fixing plate 13B are placed in alignment with mounting holes 11 band 11 b formed in the mounting surface 11B of the holding portion 11for receiving not shown fastening bolts which are inserted and tightenedfrom outside of the holding portion 11. Thus, the elastic member 13 isfixed in the holding portion 11.

[0087] A diameter d of the supporting plate 13A of the elastic member 13is set to be greater than a width dimension W of the opening 11D. Whenthe elastic member 13 is fixed in the holding portion 11, therefore, thesupporting plate 13A is brought opposite inner surfaces 11 c and 11 c ofthe frame portions 11 a and 11 a. Accordingly, when the elastic member13 is in expanded condition, the surface of the supporting plate 13A isurged onto the inner surfaces 11 c and 11 c under pressure.

[0088] Here,the inner surfaces 11 c and 11 c of the frame portions 11 aand 11 a are not parallel to the mounting surface 11B but are tilted atan angle θ such that the inner surfaces 11 c and 11 c go away from themounting surface 11B as they go away from the rocking portion 10. Itshould be noted that the fixing surface 11A on which the rocking portion10 is fixed, is at 90° with respect to the mounting surface 11B.

[0089] Therefore, when the elastic member 13 is expanded within theholding portion 11 to urge the surface of the supporting plate 13A intocontact with the inner surfaces 11 c and 11 c of the frame portions 11 aand 11 a under pressure, the surface of the supporting plate 13A is notin parallel relationship with the mounting surface 11B but tilted at thetilting angle e to increase distance to the mounting surface 11B asincreasing distance from the rocking portion 10.

[0090] The anvil 14 has a base 14A with a uniform thickness over itsentire length, and a pair of ridge portions 14B and 14B formed on thesurface of the base 14A to extend in the longitudinal direction inparallel relationship with each other. Surfaces of the ridge portions14B and 14B serve as seal opposing surfaces 14 a and 14 a to be opposedto the horn 8. The seal opposing surfaces 14 a and 14 a serve aspattering surfaces for defining a pattern of sealed portions to beformed in the continuous soft work.

[0091] The base 14A of the anvil 14 is provided at its longitudinallyopposed two ends with through holes 14A1 and 14A1, and mounted on asupport base 14C by means of not shown bolts. Furthermore, the supportbase 14C has not shown through holes formed at two positions. Byfastening with not shown bolts inserted into the tap holes 13 a and 13 aand into the through holes formed in the support base 14C, the base 14Aand the support base 14C are firmly secured on the surface of thesupporting plate 13A.

[0092] The support base 14C of the anvil 14 and the seal opposingsurfaces 14 a are parallel with each other. Therefore, in the conditionwhere the anvil 14 is fixed on the supporting plate 13A of the elasticmember 13 within the holding portion 11, the seal opposing surfaces 14 aare tilted at the tilting angle θ to increase distance to the mountingsurface 11B as increasing distance from the rocking portion 10 (rockingshaft 10A).

[0093] Next, discussion will be given for one example of a continuoussoft work 30 to be supplied to the sealing apparatus 1 with reference toFIGS. 8A and 8B. The soft work 30 is supplied to the sealing apparatus 1in folded condition as shown in FIG. 8B. FIG. 9 is a section taken alongline IX-IX of FIG. 8B and showing a condition where the sealed portionis formed, and FIG. 10 is a section taken along line X-X of FIGS. 8B and9.

[0094]FIG. 8B shows the continuous soft work 30 in which sealed portionsS has been formed with the horns 8 and the anvils 14 of the sealingapparatus 1. After forming the sealed portions S in the continuous softwork 30, the continuous soft work 30 is cut along cutting lines Cl-Clbetween adjacent sealed portions S to manufacture the pants typedisposable diapers as soft absorbent articles. On the other hand, FIG.8A show the continuous soft work 30 in developed condition.

[0095] In the developed, strip form body of FIG. 8A, a first sheet 32 ispositioned at the back, and a second sheet 31 is stacked on the firstsheet 32. The first sheet 32 has a larger width dimension than that ofthe second sheet 31. On one side 30A shown in FIG. 8A, the first sheet32 is folded back to have its side edge 32 a over the second sheet 31.Similarly, on the other side 30B, the first sheet 32 is folded back tohave its side edge 32 b over the second sheet 31. Such folded conditionis shown in FIG. 10.

[0096] As shown in FIG. 10, on one side 30A of the strip form body, aplurality of waist bands 35 are disposed between the first sheet 32 andthe second sheet 31. On the other hand, on the other side 30B of thestrip form body, a plurality of waist bands 36 are disposed between thefirst sheet 32 and the second sheet 31. The plurality of waist bands 35and 36 are arranged in parallel relationship and extend straight infeeding direction of the strip form body.

[0097] Furthermore, between the first sheet 32 and the second sheet 31,leg bands 37 and 38 are provided. In the shown embodiment, respectivelyplurality of leg bands 37 and 38 are provided. The leg bands 37 and 38are curved into waveform and extend in feeding direction of the stripform body, respectively. As shown in FIG. 8A, in regions surrounded bythe leg bands 37 and 38, there are formed leg holes 34, which will serveas leg inserting portions of pants.

[0098] The waist bands 35 and 36 and the leg bands 37 and 38 aresandwiched between the first sheet 32 and the second sheet 31 in acondition elongated in feeding direction of the strip form body by apredetermined degree of elongation. Then, the first sheet 32, the secondsheet 31, and the waist bands 35 and 36 and the leg bands 37 and 28sandwiched there between are bonded with each other by hot-melt typeadhesive or the like.

[0099] The first sheet 32 and the second sheet 31 has air permeabilityand liquid blocking ability and are heat-fusible. For instance, thefirst sheet 32 and the second sheet 31 may be spun bonded or melt blownnon-woven fabric formed from thermoplastic synthetic fibers, or alaminated sheet of the foregoing non-woven fabrics. In an alternative,one of the first sheet 32 and the second sheet 31 may be the non-wovenfabric and the other may be air permeable plastic film.

[0100] The waist bands 35 and 36 and the leg bands 37 and 38 are formedfrom elastically extensible member, such as string form or band formrubber or synthetic rubber.

[0101] On the surface of the second sheet 31, liquid absorptive bodies33 are provided between adjacent leg holes 34. The liquid absorptivebodies 33 are of hourglass shape or rectangular shape and are arrangedwith a given interval along feeding direction of the strip form body.The liquid absorptive body may be formed by wrapping crushed pulp,mixture of crushed pulp and super absorbent polymer (SAP), a laminate ofhydrophilic non-woven fabrics, air-laid pulp, or the like, in a liquidpermeable top sheet. Then, the respective liquid absorptive bodies 33are bonded on the surface of the second sheet 31 by hot-melt typeadhesive or the like.

[0102] The top sheet may be formed from spunlaced non-woven fabric,through-air bonded non-woven fabric, plastic film having apertures forliquid passage, or the like.

[0103] The continuous soft work 30 shown in FIG. 8B is formed by foldingthe strip form body shown in FIG. 8A along a longitudinally extendingcenter line O1-O1 into two ply sheet. When the soft work 30 is suppliedto the sealing apparatus 1, the soft work 30 in which the first sheet 32and the second sheet 31 are stacked, is clamped between the horn 8 andthe anvil 14 at a position between adjacent liquid absorptive bodies 33for ultrasonic sealing. As shown in FIG. 10, the soft work 30 to beclamped between the horn 8 and the anvil 14 has the smallest thicknessin the intermediate portion where four sheets (two first sheets 32 andtwo second sheets 31) are stacked.

[0104] On the other hand, the soft work 30 has the largest thickness inthe portion to be the waist side of pants where the folded-back portionsof the first sheet 32 having the side edges 32 a and 32 b are furtherstacked in addition to the four sheets and the waist bands 35 and 36 aredisposed therein. In the portion to be the leg side of pants close tothe leg holes 34, the leg bands 37 and 38 are disposed in stacked foursheets. Therefore, the thickness of the leg side is greater than that ofthe intermediate portion and smaller than that of the waist side.

[0105] Since the first sheet 32 and the second sheet 31 are formed froma heat-fusible material, they generate an internal heat due to vibrationapplied from the horn. Thus, the first sheet 32 and the second sheet 31are welded depending upon fine projection pattern formed on the sealopposing surfaces 14 a of the anvil 14 to form the sealed portion S.

[0106] In the example of FIG. 8B, a pattern of the sealed portion Sformed by the fine projection pattern is such that thin seal lines arerepeated in a row. After formation of the sealed portions S by thesealing apparatus 1, the continuous soft work 30 is cut along thecutting lines Cl-Cl between adjacent sealed portions S to complete pantstype disposable diapers as soft absorbent articles.

[0107] It should be noted that the soft absorbent article manufacturedby the sealing apparatus according to the present invention may besanitary napkin, panty liner and so forth.

[0108] Hereinafter, operation of the sealing apparatus 1 will bediscussed.

[0109] As shown in FIG. 2, the continuous soft work 30 is wound on asupply roll 21 provided at a supply portion (i) and supplied to an outerperipheral face 5A of the rotary drum 5. The continuous soft work 30 iswrapped on the outer peripheral face 5A of the rotary drum 5 (in furtherdetail on the seal opposing surfaces 8 a of the horns 8 projecting fromthe outer peripheral face 5A) over an angle of about 180°, and isreleased from the rotary drum 5 at an eject portion (ii) to beexternally withdrawn by wrapping on an eject roll 22.

[0110] The continuous soft work 30 is continuously fed to the supplyportion (i) at a constant speed. In the sealing apparatus 1, a rotarydriving force is transmitted to the timing wheel 2 to rotate the rotaryshaft 3 a, the rotary base 6 as rotating portion and the rotary drum 5in counterclockwise direction in FIGS. 2 and 3 at a constant angularvelocity.

[0111] Here, the continuous soft work 30 contact with the seal opposingsurfaces 8 a of the horns 8 projecting from the outer peripheral face 5Aof the rotary drum 5 thus rotating. Therefore, in the shown embodiment,the angular velocity of the rotating portion is set so that therotational peripheral speed of the seal opposing surfaces 8 a matcheswith the supply speed of the continuous soft work 30. Accordingly, onthe outer peripheral face 5A of the rotary drum 5, the seal opposingsurfaces 8 a of the horns 8 and the continuous soft work 30 rotatetogether without causing any slippage with respect to each other.

[0112] The circumferential arrangement pitch of the horns 8 projectingfrom the outer peripheral face 5A of the rotary drum 5 matches with thearrangement pitch of the liquid absorptive bodies 33 and the arrangementpitch of the leg holes 34 of the continuous soft work 30 shown in FIG.8B. Therefore, when the continuous soft work 30 is supplied to the outerperipheral face 5A of the rotary drum 5, the liquid absorptive body 33is located between adjacent horns 8 (between adjacent sealingmechanisms) as shown in FIG. 9, so that the seal opposing surface 8 a ofthe horn 8 confronts the portion where the liquid absorptive body 33 isnot present.

[0113] While the rotary base 6 and the rotary drum 5 are rotated incounterclockwise direction at constant speed, the follower 10 a providedin the rocking portion 10 of the rocking support member 9 moves alongthe cam groove 15 c of the cam member 15 provided on the stationarytable 4.

[0114] As shown in FIGS. 3 and 5, when the follower 10 a is moved fromthe angular position A0 to the angular position A1 in the cam groove 15c by rotation of the rotary base 6, the follower 10 a is moved toapproach to the rotation center axis O-O by the cam groove 15 c. Asshown in lower portion of FIG. 1 and FIG. 6, therefore, while thefollower is moved from the angular position A0 to the angular positionA1, the rocking support member 9 is pivoted radially outwardly about therocking shaft 10A, so that the anvil 14 held in the rocking supportmember 9 is oriented outwardly at an angle substantially 90° withrespect to the rotation center axis O-O. It should be noted that at thistime, the rocking support member 9 is pivoted within the cut-out portion15 a of the cam member 15. Therefore, the rocking support member 9 canbe pivoted up to the position where the seal opposing surface 14 a ofthe anvil 14 is placed at 90° with respect to the rotation center axisO-O.

[0115] The supply portion (i) and the eject portion (ii) for supplyingand ejecting the continuous soft work 30 are located between the angularposition A0 and the angular position A1. Between these angularpositions, the anvil 14 is pivoted to the retracted position so as notto interfere with the continuous soft work 30, away from the path of thecontinuous soft work 30 to be supplied to the rotary drum 5 and the pathof the continuous soft work 30 ejected from the rotary drum 5.Accordingly, supplying and ejecting of the continuous soft work 30 willnever be interfered by the anvil 14.

[0116] When the follower 10 a is moved from the angular position A1 andthe angular position A2, the follower 10 a is moved toward outerperiphery as guided by the cam groove 15 c. Therefore, the rockingsupport member 9 is pivoted toward the outer peripheral face 5A of therotary drum 5. When the follower 10 a moved across the angular positionA2, then, in a region of the continuous soft work 30 where the liquidabsorptive body 33 is not provided, the stacked body of the first sheet32, the second sheet 31, the waist bands 35 and 36 and the leg bands 37and 38 (see FIG. 10) is clamped by the seal opposing surface 8 a of thehorn 8 and the seal opposing surface 14 a of the anvil 14, as shown inFIG. 9. Then, this condition is maintained up to a position short of theangular position A3.

[0117] Furthermore, while the follower 10 a is moved from the angularposition A3 to the angular position A0, the follower 10 a is guided bythe cam groove 15 c toward the rotation center axis O-O, so that theanvil 14 is pivoted away from the horn 8 and the continuous soft work30. Then, when the follower 10 a reaches the angular position A0, theanvil 14 is pivoted to the retracted position angled at about 90° withrespect to the rotation center axis O-O, as shown in FIG. 6.

[0118] While the follower 10 a of each rocking support member 9 is movedfrom the angular position A2 to the angular position A3, electric poweris supplied to the ultrasonic generating means 7 for a predeterminedperiod to drive the horn 8 to vibrate for the predetermined period forforming the sealed portions S in the continuous soft work 30, as shownin FIG. 8B. At these sealed portions S, the soft work 30 isfusion-bonded. Then, the continuous soft work 30 after completion ofseal as shown in FIG. 8B is ejected by the eject roll 22. The continuoussoft work 30 ejected by the eject roll 22 is cut along the cutting lineCl-Cl shown in FIG. 8B between adjacent sealed portions S to productindividual pants type diapers.

[0119]FIG. 6 shows a condition where the rocking support member 9 ispivoted to the retracted position. At this condition, the seal opposingsurface 8 a at the leading end of the horn 8 matches with a plane Lhparallel to the rotation center axis O-O and to the outer peripheralface 5A of the rotary drum 5. The 10 rocking center of the rockingsupport member 9 (center of the rocking shaft 10A) is located on theplane Lh. In FIG. 6, a plane extending across the rocking center andperpendicular to the plane Lh is indicated at Lv. In the condition ofFIG. 6, the mounting surface 11B of the holding portion 11 of the 15rocking support member 9 is parallel to the plane Lv.

[0120] In the condition of FIG. 6, the seal opposing surface 14 a of theanvil 14 pivoted to the retracted position is slightly projected towardthe horn 8 beyond the plane Lv. The projecting amount is compressionmargin of the elastic member 13 when the anvil 14 is pressed onto thehorn 8 as reached in clamping position.

[0121] Air supply to the elastic member 13 via the nozzle 13 b iscontrolled to provide a predetermined internal pressure. In thecondition shown in FIG. 6, the supporting plate 13A of the elasticmember 13 is urged onto the tilted inner surfaces 11 c of the frameportions 11 a of the holding portion 11 by the internal pressure of theelastic member 13. Therefore, the seal opposing surface 14 a of theanvil 14 is tilted at the tilting angle θ with respect to the plane Lvto increase projecting amount from the plane Lv as increasing distancefrom the rocking shaft 10A.

[0122] While the follower 10 a is moved from the angular position A1 tothe angular position A2 as shown in FIGS. 3 and 5, the rocking supportmember 9 is pivoted toward the outer peripheral face 5A of the rotarydrum 5. At the final stage of the pivoting operation, the seal opposingsurface 14 a of the anvil 14 abuts onto the seal opposing surface 8 a ofthe horn 8 with clamping the continuous soft work 30 as shown in FIG.7A.

[0123] Here, in FIG. 6, the seal opposing surface 14 a of the anvil 14is tilted toward contacting direction with the horn 8 as increasingdistance from the rocking center. Therefore, as shown in FIG. 7A, whenthe rocking support member 9 is pivoted over an angle (90°-θ) from thecondition of FIG. 6, the seal opposing surface 14 a of the anvil 14 isplaced substantially parallel to the seal opposing surface 8 a of thehorn 8.

[0124] Then, when the following 10 a reaches the angular position A2 andthe rocking support member 9 is pivoted over 90° from the plane Lv asshown in FIG. 7B, the surface of the supporting plate 13A of the elasticmember 13 is placed away from the inner surfaces 11 c of the frameportions 11 a of the holding portion 11. Then, the mounting surface 11B,the supporting plate 13A and the seal opposing surface 14 a are placedin parallel or substantially parallel relationship with each other. Theanvil 14 is subject to elastic force of the elastic member 13 to beelastically pressed toward the horn 8.

[0125] As set forth above, since the seal opposing surface 14 a of theanvil 14 is projected from the plane Lv with the tilting angle θ in thecondition shown in FIG. 6, the seal opposing surface 8 a of the horn 8and the seal opposing surface 14 a of the anvil 14 come into contactwith each other in parallel or substantially parallel relationship inthe condition shown in FIG. 7A. Subsequently, elastic pressure from theelastic member 13 acts on the anvil 14. Accordingly, when the anvil 14is urged onto the horn 8 under pressure by pivoting motion, displacementmotion of the seal opposing surface 14 a of the anvil 14 relative to thesealing opposing surface 8 a of the horn 8 along the plane Lh is hardlycaused.

[0126] This is because, when the seal opposing surface 14 a of the anvil14 and the seal opposing surface 8 a of the horn 8 begin to contact,these surfaces contact as parallel surfaces. In addition, the sealopposing surfaces 8 a and 14 a are hardly damaged. Moreover, since theclamping of the continuous soft work 30 is performed by parallelsurfaces, the continuous soft work 30 can be certainly clamped betweenthe seal opposing surface 8 a and the seal opposing surface 14 a.

[0127] On the other hand, when the continuous soft work 30 is thecontinuous body of the pants type disposable diapers, the continuoussoft work 30 is not flat in the portion where the sealed portion S is tobe formed with the horn 8 and the anvil 14, as shown in FIG. 10. Namely,the thickness is the largest in the waist side, decreased in theintermediate portion, and then increased in the leg side. Accordingly,the soft work 30 to be sealed is locally different in thickness and hasunevenness on the surface.

[0128] As set forth above, although the portion forming the sealedportion S does not have uniform thickness and varies in thickness overdifferent portions thereof, because the anvil 14 is urged toward thehorn 8 by an air dumper i.e., the bag shaped elastic body filled withair (fluid), the seal opposing surface 14 a of the anvil 14 can flexiblyfollow to variation of the thickness of the continuous soft work 30.Furthermore, by the internal pressure of the elastic body 13, thecontinuous soft work 30 can be substantially uniformly depressed atrespective portions of the sealed portion S by the horn 8 and the anvil14. Thus, seal quality of the sealed portion S can be made uniform.

[0129] On the other hand, the internal pressure inside of the bag bodyof the elastic member 13 can be controlled by supply of air pressurethrough the nozzle 13 b. Therefore, control for varying the internalpressure inside of the bag body of the elastic member 13 is facilitateddepending upon the material and structure of the continuous soft work 30to be sealed. Accordingly, even when the structure of the continuoussoft work 30 is varied and associating therewith, the seal pattern onthe seal opposing surface 14 a of the anvil 14 is varied, preparationcan be completed merely by changing the internal pressure of the elasticmember 13 to permit sealing operation under optimal condition,constantly.

[0130] Furthermore, in the sealing mechanism of this embodiment, sincemechanism to perform sealing after clamping the continuous soft work 30is employed, sealing condition can be constantly maintained at anyproduction speed by setting power supply period to the ultrasonicgenerating means 7 at a given period and by setting the sealing pressureat a predetermined magnitude. Thus, various production speeds can berealized.

[0131] Also, it is preferred to mount the ultrasonic generating means 7in movable manner along normal direction (radial direction) with respectto the rotary drum 5 so that the projection height h of the leading endof the horn 8 from the outer peripheral face 5A of the rotary drum 5 canbe varied. By taking such construction, the projection height h can bevaried depending upon the thickness of the liquid absorptive body 33 ofthe soft work 30 to certainly seal the sheets for any product providedwith the liquid absorptive body.

[0132] On the other hand, when the continuous soft work 30 is formed byfolding even the liquid absorptive bodies 33 together with respectivesheets, as shown in FIG. 8B, the projection height h shown in FIG. 9 ispreferably one half of the thickness T of the continuous soft work 30 atthe portion where the liquid absorptive body 33 is provided. Namely, itis preferred that the projection height h is substantially equal to thethickness of the liquid absorptive body 33 in developed condition.

[0133] By setting as set forth above, in the portion where the liquidabsorptive body 33 is not provided, the sheets 31 and 32 can becertainly clamped by the horn 8 and the anvil 14 without beinginfluenced by the thickness of the liquid absorptive body 33.

[0134] In the shown embodiment, the horn 8 is fixed on the side of therotation center axis O-O and the anvil 14 is provided rockably outwardlyof the horn 8. However, conversely, it is also possible that the anvil14 is fixed on the side of the rotation center axis O-O and the horn 8is provided for rocking motion. On the other hand, the sealing mechanismmay be a heat sealing mechanism for establishing seal by heating a firstclamping member and a second clamping member and clamping the continuoussoft work with these first and second clamping members.

[0135] In the first embodiment, on the other hand, the rocking drivingmeans is formed from the follower 10 a projecting from the rockingsupport member 9 and the cam groove 15 c formed in the cam member 15.However, conversely, it is also possible that a projecting cam followeris formed in the cam member and a recess or groove to be guided alongthe projecting cam follower is formed in the rocking support member.

[0136] As the rocking driving means for driving the rocking supportmember 9, a cylinder mechanism or the like or a link mechanism whichwill be discussed later in discussion for the second embodiment may alsobe employed.

[0137] On the other hand, the elastic member 13 for biasing the anvilmay be a coil spring or the like in place of the elastic memberdiscussed above.

[0138] FIGS. 11 to 14 show a sealing apparatus 40 according to a secondembodiment of the present invention. FIG. 11 is a vertical section ofthe sealing apparatus 40, FIG. 12 is a front elevation showing astructure of a cam member, FIG. 13 is a side elevation showing asupporting condition of the anvil 14, and FIG. 14 is an illustrationshowing a construction of a piping for setting internal pressure ofelastic members.

[0139] The sealing apparatus 40 shown in FIG. 11 is different from thesealing apparatus 1 of the first embodiment only in constructions of therocking driving means and the ultrasonic generating means, number of theelastic members supporting each anvil 14, and an internal pressuresetting condition for respective elastic members. Other constructionsare substantially the same as the first embodiment.

[0140] Namely, the soft work 30 to be continuously supplied is similarto that shown in FIGS. 8A, 8B to 10. Seal timings A0, A1, A2 and A3 ofthe sealing mechanism are the same as those of the sealing apparatus 1.Furthermore, the position of the rotation center of the rocking supportmember, the tilting angle θ of the anvil 14 when the rocking supportmember is pivoted to the retracted position, relative motion of theanvil 14 and the horn 8 when the anvil 14 is pivoted to abut on the horn8, the optimal value of the projecting height h of the horn 8 from therotary drum 5 and so forth are the same as the sealing apparatus 1.

[0141] It should be noted that, in the following disclosure, likecomponents to those of the sealing apparatus 1 of the first embodimentwill be identified by like reference numerals and detailed discussiontherefore will be eliminated for avoiding redundant discussion andwhereby to keep the disclosure simple enough to facilitate clearunderstanding of the present invention.

[0142] The sealing mechanism in the sealing apparatus 40 shown in FIGS.11 and 12, is an ultrasonic sealing apparatus comprising the horn 8 asthe first clamping member and the anvil 14 as the second clampingmember. Different from the first embodiment, the horn 8 is driven by aplurality of ultrasonic generating means 7 to vibrate. In the embodimentshown in FIG. 11, in each of sealing mechanisms radially arranged in therotary drum 5, two ultrasonic generating means 7A and 7B are provided.Two ultrasonic generating devices 7A and 7B are arranged along the widthdirection of the rotary drum 5, namely the direction of the rotationcenter axis O-O of the rotary drum 5. When the horn 8 is driven by theultrasonic generating means 7A and 7B thus arranged to vibrate, outputof ultrasonic vibration to be applied to the soft work 30 from the horn8 can be enhanced.

[0143] As shown in FIG. 10, in the portion forming the sealed portion Sof the soft work 30, the thickness of the stacked body is large in thewaist side and the leg side. Accordingly, by arranging two ultrasonicgenerating devices 7A and 7B along the rotation center axis O-O,ultrasonic vibration can effectively act on the thick portions of thesoft work 30 for uniformly fusion-bonding overall seal region of thesoft work 30.

[0144] It should be noted that, in each sealing mechanism, ultrasonicvibration is applied to the common horn 8 by two ultrasonic generatingmeans 7A and 7B in the shown embodiment. However, it is also possible toprovide two horns and to support respective horns by respectiveultrasonic generating means 7A and 7B.

[0145] The rotary drum 5 is fixed on the rotary base 6 of equilateralhexagonal front elevation as shown in FIG. 12. At the center portion ofeach edge of the equilateral hexagonal shape of the rotary base 6, therocking support member 50 is supported. Accordingly, the rocking supportmembers 50 are spaced 60° from each other. The rocking support member 50is constructed to include a rocking portion 51 and a holding portion 52.The rocking portion 51 and the holding portion 52 are fixed with eachother. Each rocking portion 51 is rockably supported on the edge of therotary base 6 by a rocking shaft 51A. It should be noted that therocking shaft 51A is oriented perpendicular to the rotation center axisO-O.

[0146] On the surface of the stationary table 4 opposing to the rotarybase 6, a cam member 60 forming the rocking driving means is secured.The cam member 60 is of flat plate shape having a predeterminedthickness, and is formed with a cam groove 61 to be a cam profile on thefront surface. The cam groove 61 is continuous around the rotationcenter axis O-O. A depth direction of recessed portion of the cam groove61 is oriented in parallel to the rotation center axis O-O.

[0147] As shown in FIG. 11, a link mechanism is provided between therocking portion 51 and the cam member 60. In the link mechanism, a drivelink 53 is pivotably supported on the rocking portion 51 through aconnection shaft 51B provided in an orientation perpendicular to therotation center axis O-O.

[0148] On the back surface of the rotary base 6, a base portion 54A of apivotal link 54 is pivotably supported by a support shaft 54 a. Theaxial direction of the support shaft 54 a is parallel to the rotationcenter axis O-O. The leading end of the drive link 53 is pivotablyconnected to the leading end portion of an arm portion 54B of thepivotal link 54 through a connection shaft 55. The axial direction ofthe connection shaft 55 is parallel to the rotation center axis O-O.

[0149] On the pivotal link 54, the driving member 56 is mounted. Thedriving member 56 includes a driving support body 56 a fixed at theintermediate portion of the pivotal link 54 in non-pivotable fashion,and a follower 56 b provided on the driving support body 56 a. Thefollower 56 b is movable along the cam groove 61. The follower 56 a mayroll or slide without rolling along the cam groove 61.

[0150] In FIG. 12, the driving support body 56 a is eliminated for thepurpose of illustration, showing relative position between the pivotallink 54, the follower 56 b and the drive link 53.

[0151] When the rotary base 6 is rotated, the follower 56 b moves alongthe cam groove 61. At this time, a distance between the follower 56 band rotation center axis O-O is varied depending upon shape of the camgroove 61. Depending on this variation, the pivotal link 54 is pivoted,and then, the rocking support member 50 is pivoted through the drivelink 53. In the shown embodiment, the rocking driving means is formedfrom the cam member 60 and the follower 56 b.

[0152] Thus, the rocking support member 50 is pivoted by the cam groove61. Pivoting timing of the rocking support member 50 is the same as thesealing apparatus 1 of the first embodiment. When the follower 56 b ismoved from the angular position A2 to the angular position A3, therocking support member 50 is pivoted about the rocking shaft 51A towardthe outer peripheral face 5A of the rotary drum 5 to reach the clampingposition. On the other hand, while the follower 56 b is moved from theangular position A0 to the angular position A1, the rocking supportmember 50 is pivoted about the rocking shaft 51A toward the stationarytable 4 over about 90° to be placed at the retracted position.

[0153] As shown in FIGS. 11 and 13, in the second embodiment, twoelastic members 71 and 72 are provided in each holding portion 52. Twoelastic members 71 and 72 are arranged along the width direction of therotary drum 5, namely along the rotation center axis O-O.

[0154] The elastic members 71 and 72 are similar to the elastic member13 shown in FIG. 4. That is, each of the elastic members 71 and 72comprises an elastically deformable bag body, in which air as fluid issupplied.

[0155] The basic construction of the holding portion 52 is the same asthe holding portion 11 shown in FIG. 4. Two elastic members 71 and 72are fixed on a mounting surface 52B of the holding portion 52 via fixingplates 71A and 71B. At positions opposing to the mounting surface 52B,the holding portion 52 also has frame portions 51 a and 51 a similar tothe frame portions 11 a and 11 a of FIG. 4. The frame portions 51 a and51 a has inner surfaces 51 c and 51 c, which are tilted at the angle θwith respect to the plane parallel to the mounting surface 52B toapproach toward the horn 8 as increasing distance from the rocking shaft51A.

[0156] On the other ends of the elastic members 71 and 72, a supportingplate 70 is secured. On the supporting plate 70, the anvil 14 issecured. In the condition where the anvil 14 is not in contact with thehorn 8, the supporting plate 70 is urged onto the inner surfaces 51 cand 51 c by fluid pressure within the elastic members 71 and 72. As aresult, the surface of the anvil 14 has the tilting angle θ. Effect ofproviding the tilting angle θ is the same as the sealing apparatus 1 ofthe first embodiment.

[0157] On the fixing plates 71A and 71B, nozzles 73 and 74 are provided.To these nozzles 73 and 74, air pipes 75 and 76 are connected. Throughthe air pipes 75 and 76 and the nozzles 73 and 74, the internalpressures in the elastic members 71 and 72 can be set individually.

[0158] As shown in FIG. 10, in the seal region of the soft work 30 to beclamped by the horn 8 and the anvil 14, the thickness in the waist sideis greater than the thickness in the leg side. Accordingly, in the shownembodiment, the internal pressure of the elastic member 72 urging theanvil 14 at the leg side is set to be slightly higher than the internalpressure of the elastic member 71 urging the anvil at the waist side.

[0159] As a result, the anvil 14 is urged onto the horn 8 withrelatively large pressure on the leg side, and the anvil 14 is urgedonto the horn 8 with relatively small pressure on the waist side. As aresult, the soft work 30 having different thicknesses can besubstantially uniformly fusion-bonded over entire length from the waistside to the leg side. Thus, local excessive fusing can be avoided whichmight otherwise cause locally stiffening of the sealed portion S todegrade texture in final absorbent articles.

[0160] Also, since uniform seal can be formed over the portions havingmutually different thicknesses, failure of sealing is hardly caused evenwhen the internal pressures of both of the elastic members 71 and 72 arenot excessively large. Therefore, it can be avoided to apply excessivepressure on the soft work and whereby to avoid fusion of the sheet.

[0161] Individually setting of the internal pressures in the pluralityof elastic members 71 and 72 is effective in the case where the softwork 30 has portions mutually different in thickness, as set forthabove. However, it is also effective is the case where differentmaterials are distributed in the portion to be sealed, in place of or inaddition to the foregoing case. For example, when materials havingdifferent melting temperatures are distributed in different positions inthe portion to be sealed, the internal pressure of the elastic memberopposed to the material having high melting temperature is elevated; theinternal pressure of the elastic member opposed to the material havinglow melting temperature is lowered. Thus, uniform sealed portion can beformed.

[0162] It should be noted that, in the shown embodiment, the anvil 14 issingle. However, it is possible to separately provide two anvils: one tobe biased by the elastic member 71; and the other to be biased by theelastic member 72. It is also possible to provide a single anvil havinga thin portion formed between a portion supported by the elastic member71 and a portion supported by the elastic member 72 for permittingindependent behavior of the portion to be biased by the elastic member71 and the portion to be biased by the elastic member 72.

[0163]FIG. 14 shows a piping to be pressure setting means, which canvariably set the internal pressure of respective of the elastic members71 and 72 respectively provided in each sealing mechanism.

[0164] A high pressure air is applied to two pressure setting portions81 and 82 from an air pressure generating portion 80, such as air pumpor the like. One pressure setting portion 81 is adapted to set supplypressure to the elastic members 71 and 72 at a predetermined value whensealing operation is performed for the soft work 30. The other pressuresetting portion 82 is for discharging air from the elastic members 71and 72 for releasing the pressure to the supporting plate 70 by theelastic members 71 and 72. This pressure setting portion 82 is used inset-up operations such as supplying of the soft work 30 to the sealingapparatus 40 and rotating of the rotary drum 5 for a predeterminedperiod upon initiation of sealing operation, for example. The pressuresetting portions 81 and 82 may be constructed as regulators employingdiaphragms.

[0165] The pressure setting portions 81 and 82 are switched by aswitching valve 84. Forward of the switching valve 84, there is provideda pressure sensor 85. The pressure sensor 85 is designed to generate anelectric signal 85 a when the pressure within the piping is loweredacross a predetermined value. When the electric signal 85 a isgenerated, sealing operation by the sealing apparatus 40 is interrupted.

[0166] In each sealing mechanism, a pressure reducing pressure controlvalve 86 communicated with inside of the elastic member 71 through apipe 75 and a pressure reducing pressure control valve 87 communicatedwith inside of the elastic member 72 through a pipe 76 are provided.During sealing operation, the pressure set by the pressure settingportion 81 is reduced by the pressure reducing pressure control valve 86to be supplied to the elastic member 71 and is reduced by the pressurereducing pressure control valve 87 to be supplied to the elastic member72.

[0167] The pressure reducing pressure control valves 86 and 87 canindividually set pressures to be supplied to the elastic members 71 and72 by adjusting an amount of valve opening. By this, as set forth above,the internal pressure of the elastic member 71 is set slightly low andthe internal pressure of the elastic member 72 is set slightly high, forexample.

[0168] Here, it is also possible to provide only two pressure reducingpressure control valves in the sealing apparatus 40: one pressurereducing pressure control valve being for simultaneously adjusting allof air pressures to be supplied to the plurality of elastic members 71;and the other pressure reducing pressure control valve being forsimultaneously adjusting all of air pressures to be supplied to theplurality of elastic members 72.

[0169] Among piping shown in FIG. 14, the pressure sensor 85 and thepressure reducing pressure control valves 86 and 87 are mounted on therotary base 6, and piping connecting the switching valve 84 and thepressure sensor 85 is arranged along the rotation center axis O-O, andis extended externally from the sealing apparatus 40 via a rotary joint.

[0170] It should be noted that even in the sealing apparatus 1 of thefirst embodiment, similar piping as that shown in FIG. 14 is provided.However, in case of the sealing apparatus 1, a single pressure reducingpressure control valve is provided for each sealing mechanism.

[0171] In the first embodiment, the construction, in which a singleelastic member 13 is provided in each holding portion 11, has beendisclosed. In the second embodiment, on the other hand, theconstruction, in which two elastic members 71 and 72 are provided ineach holding portion 52, has been disclosed. However, the presentinvention is not limited to these embodiments, and three or more elasticmembers may be provided for each holding portion.

[0172] As a result of the various structures described in detail above,advantages of the present invention may include one or more of thefollowing:

[0173] (1) Sealed portions can be formed in predetermined positions of acontinuous soft work at high speed;

[0174] (2) Clamping and unclamping of the continuous soft work by afirst clamping member and a second clamping member of sealing mechanismcan be performed quickly and certainly; and

[0175] (3) Since the clamping and unclamping can be performed only byrocking or pivoting motion of the second clamping member, operation ofthe apparatus can be simplified and construction of the apparatus can besimplified.

[0176] Particularly, if the second clamping member is pivoted by the useof a cam member, as in the foregoing embodiments, rotating force of arotating portion can be used for driving the second clamping member inclamping and unclamping directions. Therefore, the driving power sourcecan be minimized.

[0177] On the other hand, if an elastic member having a casing, intowhich fluid is to be supplied, is employed for pressing the secondclamping member, as in the foregoing embodiments, uniform pressure canbe easily applied to the soft work by the second clamping member. Inthis case, additionally, since internal pressure of the elastic membercan be freely set, initial setting can be changed only by varying theinternal pressure even if the structure of the soft work is varied, tothereby improve work efficiency. Particularly, if a plurality of elasticmembers are provided in each sealing mechanism, uniform clamping forcecan be easily applied to a soft work having locally differentthicknesses.

[0178] Although the present invention has been illustrated and describedwith respect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omission and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodied within a scope encompassed andequivalent thereof with respect to the feature set out in the appendedclaims.

1. A sealing apparatus for forming sealed portions in a soft workcontinuously fed thereto, the sealing apparatus comprising: a rotatingportion; rotating driving means for driving said rotating portion torotate; and a plurality of sealing mechanisms arranged along a rotatingdirection of said rotating portion to move along with said rotatingportion, each sealing mechanism including a first clamping member and asecond clamping member for clamping said soft work therebetween within apredetermined angular range with respect to a rotation center of saidrotating portion for forming said sealed portions in said soft work,wherein in each sealing mechanism, said first clamping member is locatedon the side of said rotation center of said rotating portion to orient aseal opposing surface thereof outwardly in a normal direction extendingfrom said rotation center, said second clamping member corresponding tosaid first clamping member is located outside of said first clampingmember in said normal direction, and said second clamping member ispivotably supported on said rotating portion for pivoting between aclaming position, in which a seal opposing surface thereof is urgedtoward said seal opposing surface of said first clamping member, and aretracted position located away from said first clamping member, andwherein rocking driving means is provided for driving said secondclamping member to pivot as the rotating portion rotates so that saidsecond clamping member is located in said clamping position within saidpredetermined angular range and located in said retracted positionwithin another angular range so as not to interfere with feeding of saidsoft work into said sealing mechanisms and ejecting of said soft workfrom said sealing mechanisms.
 2. A sealing apparatus as set forth inclaim 1, wherein said continuous soft work includes at least a sheetwhich can be fusion-bonded.
 3. A sealing apparatus as set forth in claim2, wherein said continuous soft work further includes liquid absorptivebodies spaced apart from each other in a feeding direction thereof andsupported by said sheet, and sealing is effected in a condition whereeach liquid absorptive body is located between adjacent sealingmechanisms and said sheet is folded back.
 4. A sealing apparatus as setforth in any of claims 1 to 3, wherein said rotating portion includes arotary drum, and said first clamping member is arranged inside of saidrotary drum so that said seal opposing surface of said first clampingmember is located at a position projecting from an outer peripheral faceof said rotary drum.
 5. A sealing apparatus as set forth in any ofclaims 1 to 4, wherein said seal opposing surface of said secondclamping member as pivoted to said retracted position is pivoted overabout 90° with respect to a rotation center axis of said rotatingportion.
 6. A sealing apparatus as set forth in any of claims 1 to 5,wherein said rocking driving means is formed from a cam profile fixed ata position opposing to said rotating portion and a follower to movealong said cam profile as said rotating portion rotates for pivotingsaid second clamping member between said clamping position and saidretracted position.
 7. A sealing apparatus as set forth in claim 6,wherein said cam profile is defined by a continuous cam groove extendingto surround said rotation center of said rotating portion but spacedaway from said rotation center.
 8. A sealing apparatus as set forth inclaims 6 or 7, wherein said follower is mounted on a rocking supportmember supporting said second clamping member so that said rockingsupport member is pivoted between said clamping position and saidretracted position by movement of said follower along said cam profile.9. A sealing apparatus as set forth in claims 6 or 7, which furthercomprises a rocking support member supporting said second clampingmember and a link mechanism provided between said rocking support memberand said follower so that said rocking support member is pivoted betweensaid clamping position and said retracted position via said linkmechanism by movement of said follower along said cam profile.
 10. Asealing apparatus as set forth in claim 1, wherein said rotating portionincludes a rocking support member pivotably supported by a rockingshaft, and said second clamping member is supported on said rockingsupport member via an elastic member so that when said second clampingmember is pivoted to said clamping position, said second clamping memberis biased toward said first clamping member by an elastic forcedeveloped by said elastic member.
 11. A sealing apparatus comprising: asealing mechanism having a first clamping member and a second clampingmember for clamping a fusion-bondable soft work therebetween for formingsealed portions in said soft work; and driving means for driving saidsecond clamping member to clamp said soft work between said firstclamping member and said second claming member and to move away fromsaid first clamping member, wherein said second clamping member issupported on a supporting member via an elastic member and saidsupporting member is driven by said driving means so that said secondmember is biased toward said first clamping member by an elastic forcedeveloped by said elastic member, and said elastic member has adeformable casing into which fluid is introduced.
 12. A sealingapparatus as set forth in claim 11, wherein said soft work iscontinuously fed to said sealing apparatus and a plurality of sealingmechanisms are arranged at intervals along a feeding direction of saidcontinuous soft work so that said sealed portions are formed in saidcontinuous soft work at intervals along said feeding direction by meansof said sealing mechanisms.
 13. A sealing apparatus as set forth inclaims 11 or 12, which further comprises a rotating portion, and whereina plurality of sealing mechanisms are arranged at intervals along arotating direction of said rotating portion and said soft work iscontinuously fed to said rotating portion so that, as said rotatingportion rotates, said sealed portions are formed in sequential order bymeans of said sealing mechanisms.
 14. A sealing apparatus as set forthin claims 12 or 13, wherein said continuous soft work includes a sheetwhich can be fusion-bonded and liquid absorptive bodies spaced apartfrom each other in a feeding direction thereof and supported by saidsheet, and sealing is effected in a condition where each liquidabsorptive body is located between adjacent sealing mechanisms and saidsheet is folded back.
 15. A sealing apparatus as set forth in any ofclaims 11 to 14, which further comprises pressure setting means forvarying pressure of fluid within said casing.
 16. A sealing apparatus asset forth in any of claims 11 to 14, wherein a plurality of elasticmembers for supporting said second clamping member are provided in saidsupporting member.
 17. A sealing apparatus as set forth in claim 16,which further comprises pressure setting means for individually settingpressure of fluid within respective casing of said plurality of elasticmembers.
 18. A sealing apparatus as set forth in any of claims 11 to 17,wherein said sealing mechanism is an ultrasonic sealing device, and oneof said first clamping member and said second clamping member is a hornand the other is an anvil.
 19. A method for manufacturing soft articlesrespectively having sealed portions, comprising: forming sealed portionsin a continuous soft work by clamping said soft work between a firstclamping member and a second clamping member, said first clamping memberand said second clamping member forming a sealing mechanism; and cuttingsaid soft work before, simultaneously with or after the forming step,wherein said second clamping member is biased toward said first clamingmember via an elastic member and said elastic member has a deformablecasing into which fluid is introduced.
 20. A manufacturing method as setforth in claim 19, wherein a plurality of sealing mechanisms arearranged at intervals along a feeding direction of said continuous softwork so that said sealed portions are formed in said continuous softwork at intervals along said feeding direction by means of said sealingmechanisms.
 21. A manufacturing method as set forth in claim 20, whereina plurality of sealing mechanisms are arranged at intervals along arotating direction of a rotating portion and said continuous soft workis fed to said rotating portion so that, as said rotating portionrotates, said sealed portions are formed in sequential order by means ofsaid sealing mechanisms.
 22. A manufacturing method as set forth in anyof claims 19 to 21, wherein fluid pressure in said casing is set at apredetermined value.
 23. A manufacturing method as set forth in any ofclaims 19 to 22, wherein a plurality of elastic members are provided andrespective elastic members bias said second clamping member.
 24. Amanufacturing method as set forth in claim 23, wherein internalpressures of said plurality of elastic members are set independently.25. A manufacturing method as set forth in any of claims 19 to 24,wherein said continuous soft work has portions having differentthicknesses in a region where said sealed portions are to be formed. 26.A manufacturing method as set forth in claim 24, wherein said continuoussoft work has portions having different thickness in a region where saidsealed portions are to be formed, and internal fluid pressure of theelastic member biasing said second clamping member toward a portionhaving larger thickness in said soft work and internal fluid pressure ofthe elastic member biasing said second clamping member toward a portionhaving smaller thickness in said soft work are set independent of eachother.
 27. A manufacturing method as set forth in any of claims 19 to26, wherein said continuous soft work includes a sheet which can befusion-bonded and liquid absorptive bodies spaced apart from each otherin a feeding direction thereof and supported by said sheet, and sealingis effected at positions between adjacent liquid absorptive bodies in acondition where said sheet is folded back.
 28. A manufacturing method asset forth in any of claims 19 to 27, wherein said sealing mechanism isan ultrasonic sealing device, and one of said first clamping member andsaid second clamping member is a horn and the other is an anvil.